An in vitro study of secondary caries-like lesions at fissure sealings

Objective To evaluate the secondary caries-like lesions at fissure sealings in an in vitro microbial-based model.MethodTwenty-four extracted premolar teeth were selected and divided into two groups: non-saliva contamination group was sealed with a resin-based fissure sealant after phosphoric acid etching,saliva contamination group was slightly moistened with saliva before sealant application.After thermo-cycling,the specimens were incubated in broth inoculated with strains of s.mutans and s.sorbrinus for 14 days,using a sequential batch culture technique.The polarization microscope was used to observe the surface of enamel specimens.Degree of mineralization was assessed with confocal laser scanning microscope(CLSM) by measuring four lesion parameters(area,total and average fluorescence,maximum depth of the wall lesion).The data were collected and analyzed with T test.ResultsHigher numbers of secondary caries-lesion were found in saliva contamination group.There was significant difference regarding the degrees of the secondary carious lesions between the two groups.ConclusionA model of caries-like lesions at fissure sealing is established,which suggests that saliva contamination should be controled in sealant placement.